1. Field of the Invention
The present invention relates generally to mobile robotic devices, and more particularly, to an obstacle-detectable mobile robotic device.
2. Description of the Related Art
U.S. Pat. No. 6,594,844 disclosed an obstacle detection system for an autonomous cleaning robot, on which an optical emitter and a photon detector are mounted for emission and reception respectively on a surface, like the ground, that the robot travels. As a projection area generated by the optical emitter on the surface overlaps a detection area generated by the photon detector on the surface, the light emitted from the optical emitter is received by the photon detector; meanwhile, the robot is located on the smooth ground. While the robot travels and encounters a stair or a cavity, i.e. the surface on which the robot travels suddenly lowers its position, the projection area and the detection area do not overlap each other to enable the robot to regard it as encountering a barrier.
Although the above-mentioned prior art can overcome the problem while encountering the barrier, there is still space for improvement because of the following drawbacks. Generating the projection and detection areas directly on the ground by the optical emitter and the photon detector is vulnerable to the interference of external light pollution. In other words, if any external polarized light is reflected to project itself on the photon detector, misjudgment will be incurred. In addition, if the external light directly enters the detection area, the photon detector may do the misjudgment thereof due to detecting the external light.